Aromatic polyethersulphones having --OCH2 COR end groups

Abstract

Aromatic polyethersulphones that are particularly useful as adhesives and coatings having end groups of formula -OCH2COR, where R is alkyl or alkoxy. Preferred examples are -OCH2COCH3 and -OCH2COOC2H5. Such polymers may be made by heating polyethersulphones made from halophenates or bisphenate/dihalide mixtures, in the presence of a reagent of formula XCH2COR (X is halogen, preferably chlorine), such as chloroacetone or ethyl chloroacetate, for a short period of time. Such polymers of molecular weight (RV<0.25) are of particular use in coating compositions comprising a dispersion of a fluorocarbon polymer dispersed in a solution or dispersion of the polyethersulphone.

I claim: 
     
       1. An aromatic polyethersulphone containing repeat units of the general formula   --E--O--E'--O--     or, where E is the same as E',     --E--O--     in which E is the residuum obtained by the removal of the halogen atoms of a dihalobenzenoid compound in which each halogen atom is activated by an --SO 2  -- group ortho or para thereto, and E' is the residuum obtained by removal of the hydroxyl groups from a bisphenol; or where E is the same as E', it is the residuum obtained by the removal of the halogen atom and the hydroxyl group from a halophenol in which the halogen atom is activated by an --SO 2  -- group ortho or para thereto, said polyethersulphone having from 3 to 20 end groups of the formula --OCH 2  COR where R is alkyl or alkoxy, per 100 repeat units.   
     
     
       2. An aromatic polyethersulphone according to claim 1 wherein the end groups are groups having the formula --OCH 2  COCH 3  or --OCH 2  COOC 2  H 5 . 
     
     
       3. An aromatic polyethersulphone according to claim 1 wherein the end groups have the formula ##STR13## 
     
     
       4. An aromatic polyethersulphone according to claim 1 wherein said polyethersulphone has a reduced viscosity, as measured at 25° C. as a solution of the polymer in dimethyl formamide; the solution containing 1 g of polymer in 100 ml of solution, of less than 0.25 dl.g -1 . 
     
     
       5. A process for the production of an aromatic polyethersulphone in which 3 to 20 of the end groups per 100 repeat units are groups having the formula --OCH 2  COR where R is alkyl or alkoxy, wherein said process comprises heating (i) an alkali metal halophenate, or   (ii) a mixture of substantially equimolar proportions of (a) an alkali metal bisphenate, or   (b) a bisphenol and an alkali metal carbonate or bicarbonate, and a dihalobenzenoid compound, in which halophenate or dihalobenzenoid compound each halogen atom is activated by an --SO 2  -- group ortho or para thereto, and then heating the polyethersulphone so formed under anhydrous conditions with a reagent of formula XCH 2  COR, where X is halogen, and R is alkyl or alkoxy, to form the aromatic polyethersulphone.       
     
     
       6. A process according to claim 5 wherein the reagent of formula XCH 2  COR is chloroacetone or ethyl chloroacetate.